Light signal



Aprfifi 28, 1931. J. c. m K

LIGHT SIGNAL Filed Oct. 3, 1928 2 Sheets-Sheet AT'i'ORNEY FIGNQO PIC-105.,

April 28, 1931. J c, MOCK 1,802,568

LIGHT SIGNAL Filed Oct. 3, 1928 2 Sheets-Sheet 2 FIQQBO FIG.6.

Patented Apr. 28, 1931 UNITED STATES JAMES C. MOCK, or mrraoir. momem LIGHT SIGNAL Application filed October a, 1928. Serial No. 310,154.

This invention relates in general to railway light signals of the combined position and color light type, and has more particular reference to a signal wherein the light sources are constituted by hermetically sealed glass tubes filled with rarified gases of various characters and electrically energizable through electrodes sealed into the ends of the tubes.

One object of the present invention is to provide a light signal which will give an indication which can be read withaccuracy at great distances without blurring, this to be attained by having acontinuous bar of light, in place of a number of separate lights, as in the ordinary position light signal employing incandescent bulbs.

A further object of the invention is to provide means whereby the failure of a light source results in the automatic cutting into operation of a reserve light source. A characteristic inherent in the tubes employed, is that the breakdown or starting voltage is at least double the voltage required to maintain the tube energized, whereby, by connecting two like tubes, giving the same or different indications, in multiple across the secondary of a current limiting transformer, one of the two tubes in multiple will break down first, with the result that suiiicient current is drawn to lower the voltage across the secondtube below its break down value, so that the second tube will not then becut into operation. On failure of the first tube for any cause whatsoever, the cessation of current flow therethrough permits the terminal voltageof the transformer secondary to attain a value sufficient to break down the resistance of the second tube and in turn out it into operation. Thus provision is made against a failure of a tube, and without employing any moving parts whatsoever.

Furthermore the parts are so designed and arranged that should the two tubes in multiple by chance become energized simultaneously, the current drawn will be so large as to reduce the voltage below the operating voltage of the tubes, so that they both will momentarily become de-energized whereupon one or ant. danger of accident.

The tubes employed in this invention are filled with colorless gases and the glass employed in the tubes is substantially colorless, so that the tube is colorless when de-energized and only assumes its characteristic color, for giving its desired indication, when it is energized. In this manner all possibility of phantom indications is entirel avoided.

Further objects, purposes and c iaracteristic features of this invention will appear as the description progresses, reference being had to the accompanying drawings showing, solely by way of example, and not in any manner in a limiting sense, various embodiments of the invention. In the drawings Fi l is a diagrammatic view of one form of the invention, shown in connection with a simple form of traffic controlledtrackway means for controlling the signal.

Fig. 2 is a diagrammatic view of a modified form of the invention.

Fig. 3 is a diagrammatic view of a modified form showing a four indication high signal.

F ig. 4 is a diagrammatic view of another modified form showing a four indication high signal.

Fig. 5 is a diagrammatic view of another modified form showing a four indication high signal.

Fig. 6 is a diagrammatic view of another modified form showing a four indication high signal.

Fig. 7 is a diagrammatic view of a modified form showing a four indication dwarf signal.

Fig. 8 is a diagrammatic view of a mod ificd form showing a three indication dwarf signal,

Fig. 9 is a diagrammatic view of another modified form showing a three indication dwarf signal.

Fig. 10 is a diagrammatic view of another modified form showing a three indication dwarf signal.

. Fig. 11 is a diagrammatic view of another modified form showing a three indication dwarf signal.

Fig, 12 is a diagrammatic sectional eleva tion on line 1212 of Fig. 13, of a modified form of signal, employing a colorless objective lens and a reflector, looking in the direction of the arrows.

Fig. 13 is a diagrammatic sectional view. on line 13-43 of Fig. 12, looking in the direction of the arrows.

Referring now to the drawings, and first to Fig. 1, the invention is here shown in connection with a simple form of trackway control means.

In Fig. 1 is shown av stretch of single track formed by track rails 1, separated into insulated blocks A, B and C by insulating joints 2. Each block has a usual track battery 3 connected across the rails at the exit end of the block, and a track relay T con nected across the rails at the entrance end of the block, the direction of trai'ric being as indicated by the arrow. and 0: ch track relay has contact fingers at and 5.

The various parts associated with each signal location are identical, and are identified below by like reference characters with distinctive exponents.

At each signal location a line relay L. having a contact finger 6, and energized through a circuit including a front point of the track relay for the block next in advance- At each signal location is a signal constructed in accordance with this invention and comprising three gas filled scaled tubes 7, 8 and 9. the tube 7 being positioned vertically and giving a green light when energized. the tube 8 being positioned at an angle of 45 to the vertical andgiving a yellow light when energized, and the tube 9 being positioned horizontally and giving a red light when energized. Thus these tubes c011- stitute signal indications of both the color and position light type. The various tubes are connected up as shown in Fig. 1 to be controlled by the track and line relays T and L, a usual convention being employed on the drawings of designating opposite terminals of a source or sources of electrical energy by the letters B and C.

In the block C, a train is indicated by the wheels and axle 10, thus making this block a danger block, the block B a caution block, and the block A a clear block.

As shown in the drawing, the signal at the entrance to block C has its tube R energized through a circuit including contact finger 5 and back point of relay T thus indicating danger both by the color of the light emitted by the tube R and by its position. The signal at the entrance to block it has its tube Y energized through a circuit including contact finger 5 and front point of relay T, and contact finger (3 and back point of the line relay L thus indicating caution both by the position of the tube Y and the color of the light given off by the tube. In like manner the tube Gr of the signal at the entrance to block A is energized through a circuit including contact finger 5 and front point of relay T, and contact finger 6 and front point of relay L, to indicate clear or proceed condition.

As set forth above, the colors employed in the signals in a cordance with this invention are the usual red, yellow and green for indicating stop, caution and proceed respectively. Other colors can of course be employed. if desired, and these colors are obtained by using various rarified gases in suitable sealed tubes with electrodes sealed into the ends of the tubes so that an electric current passes from the one electrode to the other through the enclosed gas when suificient voltage is applied across the electrodes.

In the particular case described above, the red is obtained by employing neon gas in a plain transparent glass tube, the green is obtained by using mercury vapor in a tube made of substantially colorless fluorescent glass, and the yellow is obtained by employing helium gas in a tube made of substan-f tiallv transparent fluorescent glass.

The gases used in the tubes are under pressures of the order of 3*12 millimeters of mer eury, and it has been found, in actual use, that with the various gases employed as enumerated above, a very considerable variation in pressure during the life of the tube, or in the manufacture of the same, does not affect the indication display, and is thus quite different from the case with tubes filled with rarified air or like di-atomic gases.

As shown in Fig. 1 the tubes herein employed are in the form of a U, so as to outline the form of a semaphore blade. These tubes can be made, however, in any desired shape, and examples of this will appear in the description that follows.

It is clear from the above that all danger of phantom indications has been eliminated since the tubes giving the different signal aspects are colorless except when energized and hence a colored phantom when the tubes are de-energized, is quite impossible. Thus a very real danger in railroad operation is completely avoided by the signal of this invention.

Referring now' to Fig. 2, there is here shown a modified form of the invention which operates to cut into operation a second lightsource upon failure of a first light source, and all Without the employment of movable parts.

Shown in Fig. 2 is a current limiting transformer having a core 11 of suitably laminated material, on which, are primary and secondary windings P and S, the core having a leakage bridge formed by members 12 and 13, to cause a large leakage of primary flux thereacross in preference to passing through the secondary winding S, when current is being drawn from the secondary and hence choking the flux path on the arm on which the secondary is wound. The signal is similar to that shown in Fig. 1, except that each aspect employs two separate tubes 14 and 14 15 and 15 and 16 and 16 instead of a single tube, each set of tubes being connected in multiple in control circuits thesame as shown in Fig. 1. The relay fingers and contacts T and L are controlled respectively by track and line relays in the same manner as described in connection with Fig. 1 whereb the signal is energized green when both the track and line relays are up, is energized yellow when the track relay is up and the line relay is down, and is energized red when the track relay is down, regardless of whether the line relay be up or down. The complete circuits for energizing the various tubes are apparent from the drawing, and it is therefore deemed unnecessary to herein trace them in detail.

An inherent characteristic of the rare gas tubes employed in this invention is that the break-down voltage, that is, the voltage necessary to initiate flow of current through the tube, is at least twice the voltage required to maintain the tube energized after breakdown. Accordingly, with the arrangementshown, on energization of the greentube for example, as shown in Fig. 2, one or the otherof the tubes 14, 14 will undoubtedly break down first, whereupon the flow of current through this tube will so choke back primary flux from passing through {the secondary winding S of the transformerll as to reduce the secondary voltage below the value necessary for breaking down the other green tube, butstill sufficient to maintainin operation the tube already energized, Thus the tube which does not first break down becomes a reserve light source ready to be cut in on fa lure of the energized tube, since on such failure the choking effect on the transformer is removed momentarily and the transformer secondary voltage rises to equal or exceed the break-down voltage of the reserve tube. In this manner an automatic cut-in of a second tube, on failure of a first tube, is obtained, and all without the employment of any movable parts for effecting the automatic change over.

In Fig. 3 -is shown a four indication high signal, there being mounted on a signal post 17 a supporting casing 18, having various partitions 1 9 for boxing in the tubes employed for giving the various indications. In this particular form of signal there is a red light tube 20, in the form of an R, for indicating danger, a green light tube 21, in the form of a. vertical semaphore arm, for indicating clear, a yellow light tube 22 in the form of a semaphore arm inclined to the left of the vertical, and a second yellow light tube 23, in the form of a. semaphore arm, inclined 45 to the right of the vertical, one for indicating caution and the other for indicating approach restricting. Thus in this particular signal, four indications are provided, the two indications clear and danger being both color and position light signals, while the other two indications are position light signals only since they are both of the same yellow color when energized.

In Fig. 4 a somewhat different form of signal is shown in which the green and red tu es 24 and 25 respectively are in the form of a G and an S, to indicate go and stop,

while the yellow tubes 26 and 27 are similar to the corresponding ones in Fig. 3.

In Fig. 5 there is shown a somewhat different form of high signal giving four indications, the signal having a red marker light 28, as is usual-in signal practice, to identify the signal. The tubes here employed are each formed in two separate parts as, for example, the green tube 29 is constituted by two U-shaped members one vertically above the other and connected (not shown in the drawing) in series so as to constitute a single vertical arm signal indication, the tube being formed in two parts primarily to facilitate the manufacture of the same and avoid necessity for the manufacture of tubesof exclusive length and thereby cheapen the cost. The remainin tubes 30, 31 and 32 are respectively re yellow and yellow, to give signal indications in the manner described in connection with Fig. 3, for example.

The form of signal shown in Fig. 6 is similar to that in Fig. 5 and gives four indications in a similar manner by means of the two part tubes 33, 34, 35 and 36 which are respectively red, green, yellow and yellow.

The signal shown in Fig. 7 is a dwarf signal and is arranged to give four indications by means of the tubes 37, 38, 39 and 40 which are respectively red, green, yellow and yellow, when energized, and give the various signal indications in a manner described in the foregoing.

.Fi 8 shows a form of signal arranged to give ut three indications, by means of tubes 41, 42 and 43 which are respectively green, red and yellow when energized. the red tube in this case being in the form of a circle.

The dwarf signal of Fig. 9 is very similar to that shown in Fig. 8, the red tube 44 however being in the form of cross bars or a lattill tice worlt and may be either a single tube bentback and forth on itself, or a plurality of separate tubes. As here shown the red tube. 44 is mounted in a casing45 which is arranged to receive a front lens by means of screws in screw holes 46, whereby a colorless lens can be applied thereto in order to concentrate the light given off by the tube. In this manner the light can be concentrated, and since the lens is colorless, there is no resulting danger of phantom indications.

Figs. 10 and 11 show two forms of dwarf signals arranged to give three indications and having tubes which when energized have the colors indicated by the letters G, Y and R applied thereto, and indicating, respectively, green, yellow and red.

In Figs. 12 and 13 is shown a. signal unit employing a rare gas tube -17 in the form of a spiral, the tube 47 being mounted within a signal casing 48, carried on a support 49. The casing is mounted on a signal pole 5O and has a pivoted rear door 51, a colorless front objective lens 52, and a reflector 53. The lens and reflector and signal casing can all be of any desired type and the reflector can be used in connection with the lens or the reflector can be used alone and likewise the lens can be used alone. The tube 47, being colorless when de-energized, the employment of colorless lenses and of reflectors does notintroduce any danger of phantom indications. The tube 47 can be of any desired color to give the desired indication, and a plurality of signal casings can be mounted side by side or vertically above each other, or in any other desired manner, to constitute a signal having any desired number of color or position light indications. Thus the advantages of lenses and reflectors are retained with this type of light source, while the disadvantages thereof, one of the gravest of which is danger of phantoms, are avoided.

It is clear that in all of the various forms of signals described above, reserve light sources can be employed as described in connection with Fig. 2. And it is clear that in any of the forms, the tubes can be made as a single member, or as two or more separate members connectedin series as described in connection, for example with Fig. 5.

Furthermore, any of the forms of signals described above can be employed in connection with lenses and reflectors, or with but a lens or reflector, as described in connection, forexample, with Figs. 12 and 13.

Also, signals can be constituted by a plurality of light sources, some of the rare gas tube type, as described, and the others of the usual incandescent lamp, or the like, as, for example, a tube for caution and for clear, but a lamp and colored lens for danger.

The main advantages of the present invention over what has heretofore been known in light signals are three in number and can be briefly summarized as follows The light signal of this invention, while of the color light type, is colorless except when energized, and hence is colored only when it is desired to give an indication, and is colorless at other times, thus effectually preventing phantom indications.

The tubes can be arranged, as shown in Fig. 2, in connection with a current limiting transformer, to operate to cut in a reserve tube on a tube failure and thus avoid a dark signal, without, at the same time, employing any moving parts to effect this changeover of light sources.

In actual practice there is material advantage in the use of tubes as illustrated and described, as they emit a continuous bar of lightwith the result of particular advantage in the consistency with which the position of the indication can be read at great distances without the blurring which occurs with the indi vidual lights very generally employed.

The above rather specific description of one form of the present invention is given solely by way of illustration, and is not intended, in any manner whatsoever, in a limiting sense. Obviously, the invention can assume many different physical forms, and is susceptible of numerous modifications, and all such forms and modifications are intended to be included in this application, as come within the scope of the appended claims.

Having described my invention, I now claim:-

1. In a color light signal for railways, a plurality of separate light sources, circuits for electrically energizing said sources, and traflic controlled means for selectively contolling said circuits, said light sources, when energized, emitting lights of distinctive colors and being substantially colorless when tie-energized.

2. In a color light signal for railways, a plurality of separate light sources, circuits for electrically energizing said sources, traftic controlled means for selectively controlling said circuits, said light sources, when energized, emitting lights of distinctive colors and being substantially colorless when deepergized, and colorless lens means for said light sources for concentrating the emitted light. i

3. In a color light signal for railways, a plurality of separate light sources, circuits for electrically energizing said sources. traftic controlled means for selectively controlling said circuits, said light sources, when energized, emitting lights of distinctive colors and being substantially colorless when tie-energized. and reflector means for concentrating the emitted light from said sources.

4. In a color light signal for railwavs. a plurality of separate light sources, circuits for electrically energizing said sources. tra flfl l fic controlled means for selectively controlling said circuits, said light sources, when energized, emitting lights of distinctive colors and being substantially colorless when deenergized, and lens and reflector means for concentrating the light emitted by said sources.

5. In a railway trafiic controlling system,

in combination, a stretch of trackway divided into signal blocks, a wayside signal at the entrance end of each block, and traific controlled means for selecting energizing said signals, each signal including, a plurality of specially positioned colorless sealed tubes filled With colorless raritied gases such as to emit light, when energized, of distinctive colors corresponding in the case of each tube with the special position of such tube, to thus constitute a combined color and position light signal.

6. In a color light signal for railway use, in combination, a plurality,of sealed, gas filled tubes having means for the electrical energization thereof, and colorless when tie-energized, each tube, when energized, emitting light of a distinctive color, and trafic controlled means controlling the energization of said tubes. 1

In testimony whereof I afix my signature.

Jaime C. MGGIQ 

